Finding Father Urhney

Go south of the castle, and then keep going west in the swamps. You'll soon come upon a small house. Go inside, and talk to Father Urhney about Father Aereck needing help with the ghost haunting the graveyard. He will give you an amulet of ghostspeak so that you're able to talk to the ghost. (Note: You will need the amulet of ghostspeak for 8 later quests, so keep it in your bank after the quest. If you ever lose it, Father Urhney will give you another for free. It's advised to obtain multiple amulets via the drop trick just in case.) Now, go back to the graveyard in Lumbridge, and go to the marble coffin that is located in a small house by the graveyard.

Head to the Wizards' Tower, and climb down the ladder in the room directly next to the entrance. Down the ladder you will find an altar. Search the altar. The ghost's skull shall be there, but when you grab it, a skeleton will appear and attack you. Kill it or run, and make sure you have the skull in your inventory. Then, go back to the graveyard.

Talk to the ghost. He'll want you to put it in his coffin. Use the skull with the coffin and he will rest in peace. You will see his spirit disappear into the river. When you have done this, you will have finished the quest.

Note: Players who complete this quest with a Prayer level of 1 will gain 8 Prayer levels, resulting in a Prayer level of 9.